vegetable crops in north Florida. Proc. Florida State Hort. Soc. 79: time of application. Proc. Florida State Hort. Soc. 73:172-179. 139-146. 5. Ruehle, G. D. 1963. The Florida avocado industry. Fla. Agric. Exp. 3. Hensel, D. R. 1968. Response of potatoes to mulching at different Sta. Bull. 602. (page 50). planting and harvesting dates. Proc. Florida State Hort. Soc. 81: 6. Volin, R. B. and R. T. McMillan, Jr. 1973. Response of the tomato 153-158. cultivar "Walter" grown on mulch to soil fumigants. Proc. Florida 4. Locascio, S. J. and B. D. Thomson. 1960. Strawberry yield and the State Hort. Soc. 86:159-161. soil nutrient levels as affected by fertilizer rate, type of mulch and

Proc. Fla. State Hort. Soc. 89:236-238. 1976.

EDIBLE FRUITED PASSI FLORA ADAPTED TO SOUTH FLORIDA GROWING CONDITIONS Christopher W. Howell period in the early Spring where P. edulis f. flavicarpa has Rare Fruit Council, International, flowering periods during Spring, Summer, and Fall (2). Hollywood, FL 33023 The Purple Granadilla also prefers a cooler climate than the Yellow Granadilla and is susceptible to Fusarium wilt Abstract. Species of Passiflora bearing edible fruits are and more susceptible to nematodes than the Yellow Grana discussed with particular emphasis to those varieties adapted dilla, upon which it is sometimes grafted. The greatest to South Florida growing conditions. A summary is made of difference between P. edulis and P. edulis f. flavicarpa lies those Passiflora species and hybrids which are currently in their pollination requirements—most plants of the Purple being grown in the South Florida area and deals with fruit, Granadilla set fruit from their own pollen while most (but flower, and foliage characteristics as well as resistance to not all) Yellow Granadillas are pollen self-incompatible. nematodes, soil-borne fungi, and pollen self-compatibility. The hybrid between the two forms has characteristics in Some discussion is also given to high altitude Passifloras termediate between them and varies in degree of pollen which have been unsuccessful in fruiting in South Florida. self-compatibility (2). The next group of passionfruit contains the Giant Probably no other plant family is represented by as Granadilla (P. quadrangularis L.) and the Fragrant Grana many fruiting species as the Passifloraceae. The number of dilla (P. alata Dryand). The Giant Granadilla is the largest varieties grown in South Florida has increased each year of the passionfruit reaching a length of 12" and a weight due to new introductions and production of hybrids. As of 6 pounds. What's more not only is the pulp edible but the number of varieties increased so has confusion over the so is the thickened mesocarp which is eaten like a melon. identity of many Passiflora species. In the following article From my observations a hybrid of P. quadrangularis is I shall attempt to describe the major species grown locally widely grown in South Florida (probably a cross with P. as well as some of the more common hybrids. Among the alata). The Giant and Fragrant Granadillas each possess more widely grown fruiting Passifloras in South Florida are winged square stems (hence their names) and large unlobed the Yellow Granadilla (Passiflora edulis f. flavicarpa leaves. The leaves of P. quadrangularis have 10-12 lateral Degener), the Scarlet Passionflower (P. coccinea Aubl.), and veins, 6 petiolar glands, and large stipules; P. alata has a hybrid of the Giant Granadilla (P. quadrangular is L.). leaves with 7-8 lateral veins, 2-4 petiolar glands, and narrow In the first group of passionfruit are the Purple Grana stipules. The large flowers of the Giant Granadilla have dilla (P. edulis Sims), the Yellow Granadilla (P. edulis f. pinkish-white petals which remain pendalus while those flavicarpa), and hybrids between these two. The fruit of of the Fragrant Granadilla have crimson petals which lie the Purple Granadilla ranges from round to oval and in in a plane. Both the flowers and the fruit of P. alata are size is about 2" in diameter. The edible yellow pulp is highly fragrant. P. alata's fruit is thin-skinned, yellow, and sub-acid to sweet, highly aromatic, and contains black seeds, obovoid (4" 1 x I14" w) with whitish pulp. P. quad all of which is enclosed in a purple fruit. The Yellow Grana rangularis exists in two common fruiting forms. In the dilla also ranges in shape from round to oval (oval fruit smaller form the flowers are generally self-compatible and produce more pulp) and varies in size, although the fruits produce large crops of fruit 6-8" long. The other form, are usually larger than the purple form (up to 3y2" referred to as P. quadrangularis var. marocarpa Mast, has diameter); the aromatic pulp is yellow to deep orange flowers that appear to be self-incompatible but the lack and is much more acid and not of as high a quality of fruiting may be due to non-viable pollen (1), it produces as is thatof the purple form. The pulp surrounds brown larger fruit (up to 12" and 6 pounds) with fewer seeds, and seeds and is enclosed ina yellow fruit. The fruit of the smaller crops. Either of the Giant Granadilla fruits are hybrid is generally red and intermediate in characteristics yellowish-green with a pink tint, have pulp that is sub- between the yellow and purple forms with much seedling acid to sweet, and bland whitish mesocarp. The P. quad variation. The Yellow Granadilla is generally considered to rangularis hybrid has flowers and foliage that resemble be a botanical variety of the Purple Granadilla (4). Both P. alata while the fruit is more like that of P. quad varieties have variable leaves that are mostly trilobed with rangularis. two large glands at the apex of the petiole. Each species P. coccinea Aubl. (the Scarlet Passionflower) is the most also has similar white petaled flowers with a purple commonly grown red Passiflora in South Florida, it is corona. There are some slight differences between the two: usually sold in nurseries as an ornamental. Another red is P. edulis has clear green stems, leaves, and tendrils with P. vitifolia HBK., the Grape-leaved Passionfruit. Both no traces of red, P. edulis f. flavicarpa has a suffusion of species have downy stems and leaves. The leaves of P. red into its stems, leaves, and tendrils. In the purple coccinea are unlobed while those of P. vitifolia are tri form the flowers open in the early morning and close at lobed, both species have two glands on the stem at the noon while the yellow form's flowers open around noon base of the petiole. In nature, bees seldom visit red passion and close late at night. There is also a difference in the flowers and as such are pollinated by hummingbirds; locally two forms flowering cycles: P. edulis has only one flowering the flowers must be hand pollinated for fruit set. P.

236 Proc. Fla. State Hort. Soc. 89: 1976. coccinea's flowers are usually self-incompatible. The fruit and borne on a vine with oblong leaves with 2 petiolar of each species has white pulp that is generally sweet. The glands. P. laurifolia cv. 'Java' released by the USDA is fruit of the Scarlet Passionflower is round U/^-2" in diam cross compatible with all known Jamaican cultivars (3). and quite ornamental with its green stripes. Fruit of the Two other locally grown passionfruit that also require Grape-leaved Passionfruit is yellow, thin-shelled, and ovoid pollinators are the Montesa Granadilla (P. platyloba (2" 1 x I14" w) and is very fragrant. Locally a hybrid was Killip.) and Tagua-Tagua (P. serrato-digitata L.). Both produced between P. coccinea and P. vitifolia and known species will bear in South Florida when cross-pollinated, by the cultivar name 'Cordelia'. The hybrid has variable unfortunately few cultivars of each species is available. P. leaves from unlobed to trilobed and red flowers. It has not platyloba has trilobed leaves with long petioles with two yet fruited. A second hybrid of P. coccinea has been dis glands in the center and 4 large glands on the undersides tributed, this one made with P. edulis f. flavicarpa. The of its leaves. Its fruit is small and ellipsoidal with a hard foliage of this hybrid closely resembles that of the Scarlet shell; the pulp is very acid. P. serrato-digitata has 7-lobed Passionflower except that the leaves are more pointed and leaves with 2 pair of cup-shaped glands on the petiole. The the glands are on the middle of the petiole. This hybrid fruit of Tagua-Tagua is globose (I14" diam.), yellow with has not yet flowered to my knowledge. white pulp that is acid to sweet and said to resemble Another group of red Passifloras are part of the spectacu guava. lar sub-genus Tacsonia. In this sub-genus are also the P. seemanni Griseb. is a species closely related to P. pink-flowering Banana Passionfruit of the Andes. The ligularis, P. maliformis, and P. platyloba that is adapted Tacsonias are easily distinguished from other Passifloras to Sea Level. I have not seen plants growing locally but by their possession of a long calyx tube. Most Tacsonias suspect that plants are being grown in South Florida since come from high altitudes and therefore do not grow well P. seemanni is widely grown in the Tropics. The plant in South Florida. Exceptions are P. racemosa Brot. (syn. has cordate leaves with four cup-shaped petiolar glands. P. princeps Lodd.) and P. manicata (Juss.) Pers. which P. seemanni is cultivated in Australia, Hawaii, Mexico, were grown for a short time in South Florida (1). P. race and Nicaragua, and exists as an escape in some parts of mosa probably has the most outstanding flowering of any Jamaica. Passiflora-its brilliant red flowers are produced in racemes Although there are several species of Passiflora native of 8 or more at the terminal ends of its branches. It is to the United States only one bears a worthwhile fruit, usually cultivated for its flowers but in some South American the Maypop or Vine Apricot (P. incarnata L.). This little regions it is grown for its fruit. P. manicata is another lavender-flowering vine grows wild throughout the Eastern Tacsonia with red flowers and a brilliant royal blue corona. United States—as far north as Pennsylvania, as far south It has medium sized trilobed leaves and bears an edible as Florida, and as far west as Missouri (where the flowers fruit. P. manicata was introduced by the U.S.D.A. and is are usually white). This frost hardy vine dies back during under test at the present. The Banana Passionfruits (P. the Winter and suckers the following Spring. P. incarnata mollissima (HBK) Bailey, P. mixta L., P. antioquiensis has medium-sized trilobed leaves with two glands at the Karst., and others) are considered to produce the finest apex of the petiole. P. incarnata's fruit is yellow, oval juice and drinks of all the passionfruits. Unfortunately (ll/2-2" diam.), with a pulp having a melting taste similar they have not done well here. In the mountains of Hawaii to a tart apricot. The Maypop's cold-hardiness has made P. mollissima is found as an escape. In New Zealand P. it desirable to use in the production of cold-hardy Passi antio-quiensis Karst. (syn. P. van-volxemii Lemaire.) is com flora hybrids. One such hybrid has been made at the mercially grown at the higher altitudes. Both these species USDA. P. incarnata was crossed with pollen from the 'Crato' have trilobed leaves and pendulous rose-colored flowers. In Passionvine (P. cincinnata Mast.), the resulting hybrid has nature the Tacsonias freely hybridize among themselves been released under the cultivar name 'Incense'. Incense' (3). has proven hardy in Pennsylvania and Maryland. The Another high altitude passionfruit is the Sweet Grana- flowers of 'Incense' are large and quite showy, they are a dilla of Mexico (P. ligularis Juss.). The white pulp is sweet deep lavendar to blue color, almost identical to the flowers and has a distinctive flavor. The Sweet Granadilla has of P. cincinnata\ 'Incense' does not produce a viable pollen been grown on and off in Florida for over 30 years but but will set fruit when pollinated by another species. The has not fruited. This plant requires the cooler climate of 'Crato' Passionvine is one of the most vigorous growing the mountainous tropics and as such only puts out heavy Passifloras in South Florida, suckering quite freely; P. growth during the Winter months. It strongly dislikes cincinnata has pinnately compound leaves with 2 large August heat and usually does not survive it without glands near the base of the long petiole. The large purple, special care. P. ligularis can at once be recognized by the fragrant flowers of P. cincinnata are among the showiest 4-6 half-inch-long glands on the petiole of its large cordate of the Passifloraceae. Some vines of the 'Crato' Passion leaves. vine are self-compatible, while others are incompatible. The Sweet Calabash or Conch Apple (P. maliformis The fruit is yellow, li/2"2" in diameter, with a white sub- L.) is one of the better passionfruit that does well at Sea acid to sweet pulp which takes up to 3 months to mature. Level. The white sweet pulp is said to have the flavor of Hybrids have been made between P. cincinnata and P. grapes and is enclosed in a globose green to orange colored edulis and P. edulis f. flavicarpa, they have resembled the shell that is so hard that a hammer is often needed to open latter parent in foliage characteristics but have thus far it. The vine is a fast grower but is susceptible to nematodes. not flowered. The leaves are ovate with 2 glands in the center of the The last widely grown passionvine is usually grown for petiole. P. maliformis has self-compatible flowers (1). Un its flowers, although its fruit is quite edible, it is P. like P. maliformis, P. laurifolia L. (the Water Lemon or caerulea L. (the Blue Passionflower). P. caerulea has 5-7 Jamaican Honeysuckle) seldom sets fruit from its own lobed leaves and 2-4 stalked glands on the petiole. The pollen. This passionvine grows well on Florida's sandy pinkish to lavendar flowers are fragrant. This species is soils and is resistant to nematodes. The Water Lemon the parent to several hybrids, notably P. Xalato-caerulea quite often is a shy flowerer, so large crops are uncommon. Lindley (syn. P. pfordtii) the widely sold ornamental Blue The yellow to orange fruit has white, sweet pulp with the Passionflower which is a P. alata x P. caerulea cross. This flavor of pear. The fruit is ovoid (ll/2-4" 1 x H/4-2y2" w) hybrid does not produce a fruit.

Proc, Fla. State Hort. Soc. 89: 1976. 237 In conclusion it should be noted that many other literature Cited species of Passiftora are adapted to growth at sea level 1. Knight, R. J., Jr. 1969. Edible-fruited passionvines in Florida: the conditions similar to South Florida and as such should history and possibilities. Proc. Tropical Region Amer. Soc. Hort. be introduced and hybridized (1). In addition to the above Sci. 13:265-274. mentioned species there are several unidentified species 2. . 1972. The potential for Florida of hybrids between the purple and yellow passionfruit. Proc. Fla. State Hort. Soc. 85:288- growing locally, some of which have fruited in South 292. Florida. 3. Martin, F. W. and Nakasone, H. Y. 1970. The edible species of Passiflora. Econ. Bot. 24:333-343. 4. Officers of the Hawaii Agricultural Experiment Station. 1974. Pas sion Fruit Culture in Hawaii. Coop. Exten. Service, U. of Hawaii, Circular 345.

Proc. Fla. State Hort. Soc. 89:238-241. 1976.

MINERAL COMPOSITION OF AVOCADO LEAVES IN FLORIDA1 T. W. Young been reported. More information is needed before leaf University of Florida, analysis can be of measurable help in planning an efficient IFAS Agricultural Research and Education Center, fertilizer program for avocados in Florida. Recently, the 18905 S.W. 280 Street, effects of leaf age, leaf position on shoot, fruiting status of Homestead, FL 33030 the shoot, cultivar, and soil on the levels of 9 minerals in Florida avocado leaves were examined (8, 18). This paper R. C. J. Koo summarizes the range found in the mineral concn of leaves University of Florida, of several cultivars in Florida as affected by various factors. IFAS Agricultural Research and Education Center, Some steps for collecting avocado leaf samples that will Lake Alfred, FL 33850 enhance the probability of getting reproducible analytical results are listed. Additional index words, leaf analysis, mineral composition, leaf sampling, Persea americana. Materials and Methods Abstract. Avocado (Persea americana Mill.) leaves of 'Ton Leaf samples for examining the range in mineral concns nage7 frees growing on sand, muck, and calcareous rock soils were collected from mature trees of 'Tonnage/ 'Lula,' and 'Lula,' 'Taylor/ and 'Booth 8' trees on sand and rock were 'Taylor,' and 'Booth 8' on Astatula fine sand in the Ridge collected in 1974 and 1975 and analyzed for concns of N, P, district of Highlands County; from 'Tonnage' on Torry K, Ca, Mg, Mn, Cu, Zn, and Fe. Differences in levels of the muck near Canal Point in Palm Beach County; and from 9 elements occurred with differences in soil types, cultivar, 'Tonnage,' 'Lula,' 'Taylor,' and 'Booth 8' on Rockdale and fruiting status of the shoot. Variations generally were soil in the Redlands district of Dade County. greater on sand than on muck or rock soils. Higher levels of Avocados in Florida generally make 2 or more flushes Mn, Cu, and Zn were found on sand than on muck or rock, of growth at intervals of several weeks during the year. regardless of fertilizer or spray programs. There were differ After leaves of these different flushes have matured, they ences among cultivars, but no consistent trend in nutrient cannot readily be distinguished without marking for absorption was found. The rank in level of the 9 elements identification (3). It has been shown that levels of minerals was mixed and seemingly without bias among cultivars. N, in avocado leaves may vary with age (1, 3, 8, 11, 16). To P, and Mg were signicantly lower both years, and K in 1975, insure having leaves of uniform age in all sets of samples, in leaves on fruiting shoots than on nonfruiting shoots. There the shoots from which leaves were to be taken were marked was no significant effect of fruit on leaf levels of the other with plastic ribbon at the terminal when the leaves were elements examined. Branch girdling had no important effect fully expanded and hardened in May or June. Thirty non- on leaf level of minerals. The difference in level of minerals fruiting shoots on each of 3 trees of each cultivar on each in leaves of the 1st flush, and the 2nd which matured about soil were selected for sampling. In addition, 5 extra shoots a month later, was associated with leaf age. Methods for were marked by color code on each tree to substitute for sampling avocado leaves are discussed. any loss in the original 30. These shoots were located at a lit of about 3 to 8 ft around the periphery of the tree. Increased costs of fertilization have caused fruit Four-month-old leaves were sampled in 1974 and 1975. growers to seek more efficient use of fertilizer materials. Each sample consisted of one leaf from approx the middle With fruit crops in general, one approach to this has been of each of the 30 marked flushes on each tree. A 2nd set the use of leaf analysis as an aid in planning the fertilizer of samples was taken at this time from the trees on sand program. In California, the mineral concn of avocado and rock soils to examine the effects of fruiting on leaf (Persea americana Mill.) leaves has been examined ex level of minerals in these cultivars. These 30-leaf samples tensively (1, 2, 3, 4, 5, 9, 10, 11) and tentative levels of were from the midsection of fruiting shoots near the minerals to use in diagnosing the nutrient status of mature marked nonfruiting shoots on the same trees. trees have been set (5). Relatively little work on avocado Leaves (blades and petioles) of each sample were washed leaf analysis has been done in Florida. The relationship individually on both sides with soap solution, rinsed in of boron to alternate bearing (6) and a leaf analysis survey tap water, followed by 5% HC1 solution and finally in 3 in which 3 cultivars were sampled one time in 25 com changes of distilled water. They were oven-dried at 65°C mercial groves, mostly on calcareous rock soil (14), have and ground. The samples were analyzed for N, P, K, Ca, Mg, Mn, Cu, Zn, and Fe by methods described elsewhere iFlorida Agricultural Experiment Stations Journal Series No. 190. (17).

238 Proc. Fla. State Hort. Soc. 89: 1976.